Generally, a flat panel display includes a vacuum vessel having first and second substrates, each facing the other and separated from each other by a distance. Spacers are formed between the first and second substrates. In a flat panel display, electrons are emitted from electron emission sources located on the first substrate. These emitted electrons then collide with phosphor layers located on the second substrate. These collisions emit light and thereby display the desired images.
The electron emission sources located on the first substrate may comprise either hot or cold cathodes. Among the known electron emission sources comprising cold cathodes are the field emitter array (FEA) type, the metal-insulator-metal (MIM) type, the metal-insulator-semiconductor (MIS) type, the surface conduction emitter (SCE) type, and the ballistic electron surface emitter (BSE) type.
In order to force the electrons emitted from the electron emission sources on the first substrate toward the phosphor layers on the second substrate, the second substrate is kept in a high potential state. In a common flat panel display, this high potential state is maintained by positioning an anode on the second substrate. First, black layers are formed on the second substrate between each of the phosphor layers. These black layers provide screen contrast. The anode comprises a metallic film and is positioned over the black layers and the phosphor layers. To maintain a high potential state, a positive voltage of several hundred to several thousand volts, is applied to the anode.
The phosphor layers comprise phosphor particles several micrometers in size. The anode has a thickness of several hundred angstroms in order to facilitate electron transmission. When the metallic material is directly deposited on the phosphor layers, it does not uniformly cover the surface of the phosphor particles. Instead, the metallic material is intermittently broken, making it difficult to form a uniform metallic film.
Therefore, flat panel displays commonly comprise an intermediate layer located on the surface of the second substrate, over the phosphor layers and the black layers. The intermediate layer serves to flatten the surface of the second substrate. The metallic material is then deposited over the intermediate layer to form the anode. However, the intermediate layer is removed from the second substrate upon firing, leaving a predetermined gap between the anode and the phosphor layers and black layers. Accordingly, the adhesion of the anode to the second substrate is significantly weakened, and a stable anode is difficult to form.
As a result, the anode is likely to be damaged at the spacer formation area due to contact of the spacers with the surface of the anode. Consequently, the adhesive force of the spacers is weakened. After firing, the adhesive force of the phosphor layers is also weakened. The weakened adhesion of the spacers and the phosphor layers to the anode functionally limits the ability of the anode to support the phosphor layers.